fix: Add default isWater implementation and water movement penalty

utils.js

@@ -46,6 +46,14 @@ function randInt(min, max) {
 /**********************************************************************
  * MOVE & DISTANCE
  **********************************************************************/
+// Default implementation of isWater - will be overridden by terrain.js
+function isWater(x, y) {
+  return false; // Default to no water
+}
+
+// Water movement penalty constant
+const WATER_MOVEMENT_PENALTY = 0.5;
+
 function moveToward(obj, tx, ty, speed=0.4) {
   let dx = tx - obj.x;
   let dy = ty - obj.y;